The invention relates generally to a safety keyed electrical switch having at least one axially displaceable roller coupled to an orthogonally mounted contact containing push rod. A commercially available switch of this type is designed in such a manner that the roller is coupled via a connecting rod to the push rod. Provided at the side of the roller and rotatable about the same axis are catches which can be pivoted into the release position by the free ends of an approximately "H"-shaped actuating member, but, when using a simple tool, for example, a wire bent in a "U"-shape, they block the actuation of the switch.
In addition, U.S. Pat. No. 4,395,608 and its German counterpart Pat. No. DE-OS 31 00 862 discloses an electrical switch in the case of which a roller is coupled via a connecting link guide to the push rod. The connecting link guide is in mirror-symmetrical form so that the roller, starting from a central rest position, can move the push rod, when rotated in either direction by means of a "U"-shaped actuating member; in this manner it is possible, for example, to provide three possible operating orientations, which affords the user a high degree of flexibility when constructing his installations.
Since, in the case of known switch described at the beginning, the catches are designed asymmetrically, it is not possible to transfer this additional "coding", which is, however, desirable for safety reasons, to the type of switch last described.
The problem underlying the invention is to provide a "coding possibility" that can be used for switches of the type last mentioned and that can be realized with a small number of components and a small space requirement.
The solution according to the invention is defined in the following claim 1.
Further advantageous forms of the invention are indicated in the sub-claims, the importance of the individual features being made clear from the following detailed description.
A preferred embodiment of the subject of the invention is explained in detail below with reference to the attached drawings.